SPUDT Lamb Wave Delay Line With Lower Reflection Distortion
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Solution Overview
Problem
Conventional SAW delay lines suffer from high signal distortion and mechanical losses due to multiple reflections, which are exacerbated by the addition of reflectors intended to improve mechanical losses.
Innovation Solution
The use of single-phase unidirectional transducers (SPUDT) on a piezoelectric substrate, such as aluminum nitride, to generate anti-symmetric Lamb waves, reducing signal distortion and mechanical losses by directing main acoustic waves towards each other and impedance matching with a radio frequency energy source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SAW delay lines are used, then the device can provide signal delay functionality, but signal distortion and mechanical losses increase due to multiple reflections
Solution Approach 1:
The patent extracts and eliminates the reflector components from the conventional SAW delay line structure. By removing the reflectors that cause multiple reflections, the invention directly addresses the technical contradiction by reducing signal distortion and mechanical losses while maintaining the essential delay functionality through a simplified transducer arrangement.
Solution Approach 2:
Instead of using reflectors to guide acoustic waves (conventional approach), the invention inverts the approach by using unidirectional transducers that directly generate and receive acoustic waves in opposite directions. This inversion eliminates the reflection mechanism that causes signal distortion and mechanical losses.
2Loss of energy
If reflectors are added to improve mechanical losses, then acoustic wave guidance is enhanced, but signal distortion increases due to multiple reflections
Solution Approach 1:
The patent removes the reflector elements that create multiple reflections. By extracting these harmful components, the invention simultaneously improves signal quality (reducing distortion) and maintains acceptable mechanical loss performance through the unidirectional transducer design.
Solution Approach 2:
The invention converts the harmful effect of reflections into a beneficial approach by using unidirectional transducers that inherently guide acoustic waves without relying on reflections. The transducers are designed to produce acoustic waves with greatest amplitudes traveling toward each other, achieving wave guidance without the harmful multiple reflections.
3Use of energy by moving object
If conventional transducers are used, then the delay line can operate at radio frequencies, but transmission loss increases due to poor acoustic wave guiding
Solution Approach 1:
The patent applies local quality by designing transducers with specific directional characteristics at their locations. The unidirectional transducers are configured to produce acoustic waves with greatest amplitudes traveling in specific directions toward each other, creating localized optimal wave guidance that reduces transmission loss and improves signal transmission efficiency.
Solution Approach 2:
The invention changes the operational parameters of the transducers by using single-phase unidirectional design instead of conventional bidirectional transducers. This parameter change in transducer configuration improves acoustic wave guiding and reduces transmission loss while maintaining radio frequency operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The SPUDT-based delay line significantly reduces signal distortion and transmission loss, improving the overall performance by minimizing reflections and enhancing acoustic wave guiding, making it suitable for high-frequency applications like 5G radio frequency devices.
Implementation Method 1
a piezoelectric substrate, a transmission single phase unidirectional transducer (SPUDT) disposed on the piezoelectric substrate
Implementation Method 2
The use of single-phase unidirectional transducers (SPUDT) on a piezoelectric substrate, such as aluminum nitride, to generate anti-symmetric Lamb waves
Data Source
AI summary
A delay line for radio frequency circuits comprises a piezoelectric substrate, a transmission single phase unidirectional transducer (SPUDT) disposed on the piezoelectric substrate, and a receive SPUDT disposed on the piezoelectric substrate and separated from the transmission SPUDT in a direction of transmission of a main acoustic wave mode utilized by the transmission SPUDT.